Revised November 1, 2020
with a reconstruction of Chongmingia (Fig. 1) with new insights into to pectoral girdle and manus along with a new nesting near the base of the scansoriopterygidae in the LRT (subset Fig. 2) close to Mei and Yi (Fig. 3).
Wang et al. 2016
reported on a head-less, ‘tail-less’ basal bird fossil, which they named Chongmingia (Fig. 1).
Unfortunately the team had some difficulty nesting Chongmingia.
They reported: “For the first analysis using the coelurosaurian matrix, the analysis produced 630 most parsimonious trees of 4523 steps (Consistency index = 0.266, Retention index = 0.578). The strict consensus tree placed Chongmingia within basal Avialae, and Chongmingia is the sister taxon of Ornithothoraces. For the second analysis focusing on phylogeny of Mesozoic birds, the analysis produced four most parsimonious trees of 1009 steps. The strict consensus tree places Chongmingia as the sister to all avialans except for Archaeopteryx, and thus Chongmingia represents the most primitive bird from the Jehol Biota uncovered to date and one of the most primitive Cretaceous birds known. However, this phylogenetic hypothesis was weakly supported by both Bremer and Bootstrap values.”
Unfortunately the team did not use several Solnhofen birds
in their phylogenetic analysis. Perhaps if they did so, like the large reptile tree (LRT, 998 [now 1752] taxa) does, then they might have recovered a single tree in which Chongmingia nests within basal Scansoriopterygidae in the LRT (Fig. 2).
I was able to see in the published photo of Chongmingia
- a small string of diminishing caudal vertebrae
- the scapula and coracoid intertwined
- reidentified some disarticulated phalanges
Nesting at the base of the derived taxa,
Mei, Yi, and the several other scansoropterygids with a longer manual 3 than 2, Chongmingia (Fig. 1) is the first step toward that morphology. AND… there is no hint of a new, elongate carpal bone. That mistake remains a myth.
Such a small tail
like the similarly short-changed Yi, would not have accommodated many rectrices (tail feathers). There is no evidence of a pygostyle. Relatives don’t have a pygostyle.
Wang M, Wang X, Wang Y and Zhou Z 2016. A new basal bird from China with implications for morphological diversity in early birds. Nature Scientific Reports 6, art. 19700, 2016.